2 * Copyright (c) 2009-2017 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "classifier.h"
19 #include "classifier-private.h"
21 #include <sys/types.h>
22 #include <netinet/in.h>
23 #include "byte-order.h"
24 #include "openvswitch/dynamic-string.h"
26 #include "openvswitch/ofp-util.h"
32 /* A collection of "struct cls_conjunction"s currently embedded into a
34 struct cls_conjunction_set
{
35 /* Link back to the cls_match.
37 * cls_conjunction_set is mostly used during classifier lookup, and, in
38 * turn, during classifier lookup the most used member of
39 * cls_conjunction_set is the rule's priority, so we cache it here for fast
41 struct cls_match
*match
;
42 int priority
; /* Cached copy of match->priority. */
44 /* Conjunction information.
46 * 'min_n_clauses' allows some optimization during classifier lookup. */
47 unsigned int n
; /* Number of elements in 'conj'. */
48 unsigned int min_n_clauses
; /* Smallest 'n' among elements of 'conj'. */
49 struct cls_conjunction conj
[];
52 /* Ports trie depends on both ports sharing the same ovs_be32. */
53 #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
54 BUILD_ASSERT_DECL(TP_PORTS_OFS32
== offsetof(struct flow
, tp_dst
) / 4);
55 BUILD_ASSERT_DECL(TP_PORTS_OFS32
% 2 == 0);
56 #define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2)
59 cls_conjunction_set_size(size_t n
)
61 return (sizeof(struct cls_conjunction_set
)
62 + n
* sizeof(struct cls_conjunction
));
65 static struct cls_conjunction_set
*
66 cls_conjunction_set_alloc(struct cls_match
*match
,
67 const struct cls_conjunction conj
[], size_t n
)
70 size_t min_n_clauses
= conj
[0].n_clauses
;
71 for (size_t i
= 1; i
< n
; i
++) {
72 min_n_clauses
= MIN(min_n_clauses
, conj
[i
].n_clauses
);
75 struct cls_conjunction_set
*set
= xmalloc(cls_conjunction_set_size(n
));
77 set
->priority
= match
->priority
;
79 set
->min_n_clauses
= min_n_clauses
;
80 memcpy(set
->conj
, conj
, n
* sizeof *conj
);
87 static struct cls_match
*
88 cls_match_alloc(const struct cls_rule
*rule
, ovs_version_t version
,
89 const struct cls_conjunction conj
[], size_t n
)
91 size_t count
= miniflow_n_values(rule
->match
.flow
);
93 struct cls_match
*cls_match
94 = xmalloc(sizeof *cls_match
+ MINIFLOW_VALUES_SIZE(count
));
96 ovsrcu_init(&cls_match
->next
, NULL
);
97 *CONST_CAST(const struct cls_rule
**, &cls_match
->cls_rule
) = rule
;
98 *CONST_CAST(int *, &cls_match
->priority
) = rule
->priority
;
99 /* Make rule initially invisible. */
100 cls_match
->versions
= VERSIONS_INITIALIZER(version
, version
);
101 miniflow_clone(CONST_CAST(struct miniflow
*, &cls_match
->flow
),
102 rule
->match
.flow
, count
);
103 ovsrcu_set_hidden(&cls_match
->conj_set
,
104 cls_conjunction_set_alloc(cls_match
, conj
, n
));
109 static struct cls_subtable
*find_subtable(const struct classifier
*cls
,
110 const struct minimask
*);
111 static struct cls_subtable
*insert_subtable(struct classifier
*cls
,
112 const struct minimask
*);
113 static void destroy_subtable(struct classifier
*cls
, struct cls_subtable
*);
115 static const struct cls_match
*find_match_wc(const struct cls_subtable
*,
116 ovs_version_t version
,
119 unsigned int n_tries
,
120 struct flow_wildcards
*);
121 static struct cls_match
*find_equal(const struct cls_subtable
*,
122 const struct miniflow
*, uint32_t hash
);
124 /* Return the next visible (lower-priority) rule in the list. Multiple
125 * identical rules with the same priority may exist transitionally, but when
126 * versioning is used at most one of them is ever visible for lookups on any
127 * given 'version'. */
128 static inline const struct cls_match
*
129 next_visible_rule_in_list(const struct cls_match
*rule
, ovs_version_t version
)
132 rule
= cls_match_next(rule
);
133 } while (rule
&& !cls_match_visible_in_version(rule
, version
));
138 /* Type with maximum supported prefix length. */
140 struct in6_addr ipv6
; /* For sizing. */
141 ovs_be32 be32
; /* For access. */
144 static unsigned int minimask_get_prefix_len(const struct minimask
*,
145 const struct mf_field
*);
146 static void trie_init(struct classifier
*cls
, int trie_idx
,
147 const struct mf_field
*);
148 static unsigned int trie_lookup(const struct cls_trie
*, const struct flow
*,
149 union trie_prefix
*plens
);
150 static unsigned int trie_lookup_value(const rcu_trie_ptr
*,
151 const ovs_be32 value
[], ovs_be32 plens
[],
152 unsigned int value_bits
);
153 static void trie_destroy(rcu_trie_ptr
*);
154 static void trie_insert(struct cls_trie
*, const struct cls_rule
*, int mlen
);
155 static void trie_insert_prefix(rcu_trie_ptr
*, const ovs_be32
*prefix
,
157 static void trie_remove(struct cls_trie
*, const struct cls_rule
*, int mlen
);
158 static void trie_remove_prefix(rcu_trie_ptr
*, const ovs_be32
*prefix
,
160 static void mask_set_prefix_bits(struct flow_wildcards
*, uint8_t be32ofs
,
161 unsigned int n_bits
);
162 static bool mask_prefix_bits_set(const struct flow_wildcards
*,
163 uint8_t be32ofs
, unsigned int n_bits
);
168 cls_rule_init__(struct cls_rule
*rule
, unsigned int priority
)
170 rculist_init(&rule
->node
);
171 *CONST_CAST(int *, &rule
->priority
) = priority
;
172 ovsrcu_init(&rule
->cls_match
, NULL
);
175 /* Initializes 'rule' to match packets specified by 'match' at the given
176 * 'priority'. 'match' must satisfy the invariant described in the comment at
177 * the definition of struct match.
179 * The caller must eventually destroy 'rule' with cls_rule_destroy().
181 * Clients should not use priority INT_MIN. (OpenFlow uses priorities between
182 * 0 and UINT16_MAX, inclusive.) */
184 cls_rule_init(struct cls_rule
*rule
, const struct match
*match
, int priority
)
186 cls_rule_init__(rule
, priority
);
187 minimatch_init(CONST_CAST(struct minimatch
*, &rule
->match
), match
);
190 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
192 cls_rule_init_from_minimatch(struct cls_rule
*rule
,
193 const struct minimatch
*match
, int priority
)
195 cls_rule_init__(rule
, priority
);
196 minimatch_clone(CONST_CAST(struct minimatch
*, &rule
->match
), match
);
199 /* Initializes 'dst' as a copy of 'src'.
201 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
203 cls_rule_clone(struct cls_rule
*dst
, const struct cls_rule
*src
)
205 cls_rule_init__(dst
, src
->priority
);
206 minimatch_clone(CONST_CAST(struct minimatch
*, &dst
->match
), &src
->match
);
209 /* Initializes 'dst' with the data in 'src', destroying 'src'.
211 * 'src' must be a cls_rule NOT in a classifier.
213 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
215 cls_rule_move(struct cls_rule
*dst
, struct cls_rule
*src
)
217 cls_rule_init__(dst
, src
->priority
);
218 minimatch_move(CONST_CAST(struct minimatch
*, &dst
->match
),
219 CONST_CAST(struct minimatch
*, &src
->match
));
222 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
223 * normally embedded into a larger structure).
225 * ('rule' must not currently be in a classifier.) */
227 cls_rule_destroy(struct cls_rule
*rule
)
228 OVS_NO_THREAD_SAFETY_ANALYSIS
230 /* Must not be in a classifier. */
231 ovs_assert(!get_cls_match_protected(rule
));
233 /* Check that the rule has been properly removed from the classifier. */
234 ovs_assert(rule
->node
.prev
== RCULIST_POISON
235 || rculist_is_empty(&rule
->node
));
236 rculist_poison__(&rule
->node
); /* Poisons also the next pointer. */
238 minimatch_destroy(CONST_CAST(struct minimatch
*, &rule
->match
));
241 /* This may only be called by the exclusive writer. */
243 cls_rule_set_conjunctions(struct cls_rule
*cr
,
244 const struct cls_conjunction
*conj
, size_t n
)
246 struct cls_match
*match
= get_cls_match_protected(cr
);
247 struct cls_conjunction_set
*old
248 = ovsrcu_get_protected(struct cls_conjunction_set
*, &match
->conj_set
);
249 struct cls_conjunction
*old_conj
= old
? old
->conj
: NULL
;
250 unsigned int old_n
= old
? old
->n
: 0;
252 if (old_n
!= n
|| (n
&& memcmp(old_conj
, conj
, n
* sizeof *conj
))) {
254 ovsrcu_postpone(free
, old
);
256 ovsrcu_set(&match
->conj_set
,
257 cls_conjunction_set_alloc(match
, conj
, n
));
262 /* Returns true if 'a' and 'b' match the same packets at the same priority,
263 * false if they differ in some way. */
265 cls_rule_equal(const struct cls_rule
*a
, const struct cls_rule
*b
)
267 return a
->priority
== b
->priority
&& minimatch_equal(&a
->match
, &b
->match
);
270 /* Appends a string describing 'rule' to 's'. */
272 cls_rule_format(const struct cls_rule
*rule
, const struct tun_table
*tun_table
,
273 const struct ofputil_port_map
*port_map
, struct ds
*s
)
275 minimatch_format(&rule
->match
, tun_table
, port_map
, s
, rule
->priority
);
278 /* Returns true if 'rule' matches every packet, false otherwise. */
280 cls_rule_is_catchall(const struct cls_rule
*rule
)
282 return minimask_is_catchall(rule
->match
.mask
);
285 /* Makes 'rule' invisible in 'remove_version'. Once that version is used in
286 * lookups, the caller should remove 'rule' via ovsrcu_postpone().
288 * 'rule' must be in a classifier.
289 * This may only be called by the exclusive writer. */
291 cls_rule_make_invisible_in_version(const struct cls_rule
*rule
,
292 ovs_version_t remove_version
)
294 struct cls_match
*cls_match
= get_cls_match_protected(rule
);
296 ovs_assert(remove_version
>= cls_match
->versions
.add_version
);
298 cls_match_set_remove_version(cls_match
, remove_version
);
301 /* This undoes the change made by cls_rule_make_invisible_in_version().
303 * 'rule' must be in a classifier.
304 * This may only be called by the exclusive writer. */
306 cls_rule_restore_visibility(const struct cls_rule
*rule
)
308 cls_match_set_remove_version(get_cls_match_protected(rule
),
309 OVS_VERSION_NOT_REMOVED
);
312 /* Return true if 'rule' is visible in 'version'.
314 * 'rule' must be in a classifier. */
316 cls_rule_visible_in_version(const struct cls_rule
*rule
, ovs_version_t version
)
318 struct cls_match
*cls_match
= get_cls_match(rule
);
320 return cls_match
&& cls_match_visible_in_version(cls_match
, version
);
323 /* Initializes 'cls' as a classifier that initially contains no classification
326 classifier_init(struct classifier
*cls
, const uint8_t *flow_segments
)
329 cmap_init(&cls
->subtables_map
);
330 pvector_init(&cls
->subtables
);
331 cls
->n_flow_segments
= 0;
333 while (cls
->n_flow_segments
< CLS_MAX_INDICES
334 && *flow_segments
< FLOW_U64S
) {
335 cls
->flow_segments
[cls
->n_flow_segments
++] = *flow_segments
++;
339 for (int i
= 0; i
< CLS_MAX_TRIES
; i
++) {
340 trie_init(cls
, i
, NULL
);
345 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
346 * caller's responsibility.
347 * May only be called after all the readers have been terminated. */
349 classifier_destroy(struct classifier
*cls
)
352 struct cls_subtable
*subtable
;
355 for (i
= 0; i
< cls
->n_tries
; i
++) {
356 trie_destroy(&cls
->tries
[i
].root
);
359 CMAP_FOR_EACH (subtable
, cmap_node
, &cls
->subtables_map
) {
360 destroy_subtable(cls
, subtable
);
362 cmap_destroy(&cls
->subtables_map
);
364 pvector_destroy(&cls
->subtables
);
368 /* Set the fields for which prefix lookup should be performed. */
370 classifier_set_prefix_fields(struct classifier
*cls
,
371 const enum mf_field_id
*trie_fields
,
372 unsigned int n_fields
)
374 const struct mf_field
* new_fields
[CLS_MAX_TRIES
];
375 struct mf_bitmap fields
= MF_BITMAP_INITIALIZER
;
377 bool changed
= false;
379 for (i
= 0; i
< n_fields
&& n_tries
< CLS_MAX_TRIES
; i
++) {
380 const struct mf_field
*field
= mf_from_id(trie_fields
[i
]);
381 if (field
->flow_be32ofs
< 0 || field
->n_bits
% 32) {
382 /* Incompatible field. This is the only place where we
383 * enforce these requirements, but the rest of the trie code
384 * depends on the flow_be32ofs to be non-negative and the
385 * field length to be a multiple of 32 bits. */
389 if (bitmap_is_set(fields
.bm
, trie_fields
[i
])) {
390 /* Duplicate field, there is no need to build more than
391 * one index for any one field. */
394 bitmap_set1(fields
.bm
, trie_fields
[i
]);
396 new_fields
[n_tries
] = NULL
;
397 if (n_tries
>= cls
->n_tries
|| field
!= cls
->tries
[n_tries
].field
) {
398 new_fields
[n_tries
] = field
;
404 if (changed
|| n_tries
< cls
->n_tries
) {
405 struct cls_subtable
*subtable
;
407 /* Trie configuration needs to change. Disable trie lookups
408 * for the tries that are changing and wait all the current readers
409 * with the old configuration to be done. */
411 CMAP_FOR_EACH (subtable
, cmap_node
, &cls
->subtables_map
) {
412 for (i
= 0; i
< cls
->n_tries
; i
++) {
413 if ((i
< n_tries
&& new_fields
[i
]) || i
>= n_tries
) {
414 if (subtable
->trie_plen
[i
]) {
415 subtable
->trie_plen
[i
] = 0;
421 /* Synchronize if any readers were using tries. The readers may
422 * temporarily function without the trie lookup based optimizations. */
424 /* ovsrcu_synchronize() functions as a memory barrier, so it does
425 * not matter that subtable->trie_plen is not atomic. */
426 ovsrcu_synchronize();
429 /* Now set up the tries. */
430 for (i
= 0; i
< n_tries
; i
++) {
432 trie_init(cls
, i
, new_fields
[i
]);
435 /* Destroy the rest, if any. */
436 for (; i
< cls
->n_tries
; i
++) {
437 trie_init(cls
, i
, NULL
);
440 cls
->n_tries
= n_tries
;
444 return false; /* No change. */
448 trie_init(struct classifier
*cls
, int trie_idx
, const struct mf_field
*field
)
450 struct cls_trie
*trie
= &cls
->tries
[trie_idx
];
451 struct cls_subtable
*subtable
;
453 if (trie_idx
< cls
->n_tries
) {
454 trie_destroy(&trie
->root
);
456 ovsrcu_set_hidden(&trie
->root
, NULL
);
460 /* Add existing rules to the new trie. */
461 CMAP_FOR_EACH (subtable
, cmap_node
, &cls
->subtables_map
) {
464 plen
= field
? minimask_get_prefix_len(&subtable
->mask
, field
) : 0;
466 struct cls_match
*head
;
468 CMAP_FOR_EACH (head
, cmap_node
, &subtable
->rules
) {
469 trie_insert(trie
, head
->cls_rule
, plen
);
472 /* Initialize subtable's prefix length on this field. This will
473 * allow readers to use the trie. */
474 atomic_thread_fence(memory_order_release
);
475 subtable
->trie_plen
[trie_idx
] = plen
;
479 /* Returns true if 'cls' contains no classification rules, false otherwise.
480 * Checking the cmap requires no locking. */
482 classifier_is_empty(const struct classifier
*cls
)
484 return cmap_is_empty(&cls
->subtables_map
);
487 /* Returns the number of rules in 'cls'. */
489 classifier_count(const struct classifier
*cls
)
491 /* n_rules is an int, so in the presence of concurrent writers this will
492 * return either the old or a new value. */
496 static inline ovs_be32
minimatch_get_ports(const struct minimatch
*match
)
498 /* Could optimize to use the same map if needed for fast path. */
499 return MINIFLOW_GET_BE32(match
->flow
, tp_src
)
500 & MINIFLOW_GET_BE32(&match
->mask
->masks
, tp_src
);
503 /* Inserts 'rule' into 'cls' in 'version'. Until 'rule' is removed from 'cls',
504 * the caller must not modify or free it.
506 * If 'cls' already contains an identical rule (including wildcards, values of
507 * fixed fields, and priority) that is visible in 'version', replaces the old
508 * rule by 'rule' and returns the rule that was replaced. The caller takes
509 * ownership of the returned rule and is thus responsible for destroying it
510 * with cls_rule_destroy(), after RCU grace period has passed (see
511 * ovsrcu_postpone()).
513 * Returns NULL if 'cls' does not contain a rule with an identical key, after
514 * inserting the new rule. In this case, no rules are displaced by the new
515 * rule, even rules that cannot have any effect because the new rule matches a
516 * superset of their flows and has higher priority.
518 const struct cls_rule
*
519 classifier_replace(struct classifier
*cls
, const struct cls_rule
*rule
,
520 ovs_version_t version
,
521 const struct cls_conjunction
*conjs
, size_t n_conjs
)
523 struct cls_match
*new;
524 struct cls_subtable
*subtable
;
525 uint32_t ihash
[CLS_MAX_INDICES
];
526 struct cls_match
*head
;
527 unsigned int mask_offset
;
533 /* 'new' is initially invisible to lookups. */
534 new = cls_match_alloc(rule
, version
, conjs
, n_conjs
);
535 ovsrcu_set(&CONST_CAST(struct cls_rule
*, rule
)->cls_match
, new);
537 subtable
= find_subtable(cls
, rule
->match
.mask
);
539 subtable
= insert_subtable(cls
, rule
->match
.mask
);
542 /* Compute hashes in segments. */
545 for (i
= 0; i
< subtable
->n_indices
; i
++) {
546 ihash
[i
] = minimatch_hash_range(&rule
->match
, subtable
->index_maps
[i
],
547 &mask_offset
, &basis
);
549 hash
= minimatch_hash_range(&rule
->match
, subtable
->index_maps
[i
],
550 &mask_offset
, &basis
);
552 head
= find_equal(subtable
, rule
->match
.flow
, hash
);
554 /* Add rule to tries.
556 * Concurrent readers might miss seeing the rule until this update,
557 * which might require being fixed up by revalidation later. */
558 for (i
= 0; i
< cls
->n_tries
; i
++) {
559 if (subtable
->trie_plen
[i
]) {
560 trie_insert(&cls
->tries
[i
], rule
, subtable
->trie_plen
[i
]);
564 /* Add rule to ports trie. */
565 if (subtable
->ports_mask_len
) {
566 /* We mask the value to be inserted to always have the wildcarded
567 * bits in known (zero) state, so we can include them in comparison
568 * and they will always match (== their original value does not
570 ovs_be32 masked_ports
= minimatch_get_ports(&rule
->match
);
572 trie_insert_prefix(&subtable
->ports_trie
, &masked_ports
,
573 subtable
->ports_mask_len
);
576 /* Add new node to segment indices. */
577 for (i
= 0; i
< subtable
->n_indices
; i
++) {
578 ccmap_inc(&subtable
->indices
[i
], ihash
[i
]);
580 n_rules
= cmap_insert(&subtable
->rules
, &new->cmap_node
, hash
);
581 } else { /* Equal rules exist in the classifier already. */
582 struct cls_match
*prev
, *iter
;
584 /* Scan the list for the insertion point that will keep the list in
585 * order of decreasing priority. Insert after rules marked invisible
586 * in any version of the same priority. */
587 FOR_EACH_RULE_IN_LIST_PROTECTED (iter
, prev
, head
) {
588 if (rule
->priority
> iter
->priority
589 || (rule
->priority
== iter
->priority
590 && !cls_match_is_eventually_invisible(iter
))) {
595 /* Replace 'iter' with 'new' or insert 'new' between 'prev' and
598 struct cls_rule
*old
;
600 if (rule
->priority
== iter
->priority
) {
601 cls_match_replace(prev
, iter
, new);
602 old
= CONST_CAST(struct cls_rule
*, iter
->cls_rule
);
604 cls_match_insert(prev
, iter
, new);
608 /* Replace the existing head in data structures, if rule is the new
611 cmap_replace(&subtable
->rules
, &head
->cmap_node
,
612 &new->cmap_node
, hash
);
616 struct cls_conjunction_set
*conj_set
;
618 conj_set
= ovsrcu_get_protected(struct cls_conjunction_set
*,
621 ovsrcu_postpone(free
, conj_set
);
624 ovsrcu_set(&old
->cls_match
, NULL
); /* Marks old rule as removed
625 * from the classifier. */
626 ovsrcu_postpone(cls_match_free_cb
, iter
);
628 /* No change in subtable's max priority or max count. */
630 /* Make 'new' visible to lookups in the appropriate version. */
631 cls_match_set_remove_version(new, OVS_VERSION_NOT_REMOVED
);
633 /* Make rule visible to iterators (immediately). */
634 rculist_replace(CONST_CAST(struct rculist
*, &rule
->node
),
637 /* Return displaced rule. Caller is responsible for keeping it
638 * around until all threads quiesce. */
642 /* 'new' is new node after 'prev' */
643 cls_match_insert(prev
, iter
, new);
647 /* Make 'new' visible to lookups in the appropriate version. */
648 cls_match_set_remove_version(new, OVS_VERSION_NOT_REMOVED
);
650 /* Make rule visible to iterators (immediately). */
651 rculist_push_back(&subtable
->rules_list
,
652 CONST_CAST(struct rculist
*, &rule
->node
));
654 /* Rule was added, not replaced. Update 'subtable's 'max_priority' and
655 * 'max_count', if necessary.
657 * The rule was already inserted, but concurrent readers may not see the
658 * rule yet as the subtables vector is not updated yet. This will have to
659 * be fixed by revalidation later. */
661 subtable
->max_priority
= rule
->priority
;
662 subtable
->max_count
= 1;
663 pvector_insert(&cls
->subtables
, subtable
, rule
->priority
);
664 } else if (rule
->priority
== subtable
->max_priority
) {
665 ++subtable
->max_count
;
666 } else if (rule
->priority
> subtable
->max_priority
) {
667 subtable
->max_priority
= rule
->priority
;
668 subtable
->max_count
= 1;
669 pvector_change_priority(&cls
->subtables
, subtable
, rule
->priority
);
672 /* Nothing was replaced. */
676 pvector_publish(&cls
->subtables
);
682 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
683 * must not modify or free it.
685 * 'cls' must not contain an identical rule (including wildcards, values of
686 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
689 classifier_insert(struct classifier
*cls
, const struct cls_rule
*rule
,
690 ovs_version_t version
, const struct cls_conjunction conj
[],
693 const struct cls_rule
*displaced_rule
694 = classifier_replace(cls
, rule
, version
, conj
, n_conj
);
695 ovs_assert(!displaced_rule
);
698 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
699 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
700 * resides, etc., as necessary.
702 * Does nothing if 'rule' has been already removed, or was never inserted.
704 * Returns the removed rule, or NULL, if it was already removed.
706 const struct cls_rule
*
707 classifier_remove(struct classifier
*cls
, const struct cls_rule
*cls_rule
)
709 struct cls_match
*rule
, *prev
, *next
, *head
;
710 struct cls_conjunction_set
*conj_set
;
711 struct cls_subtable
*subtable
;
712 uint32_t basis
= 0, hash
, ihash
[CLS_MAX_INDICES
];
713 unsigned int mask_offset
;
717 rule
= get_cls_match_protected(cls_rule
);
721 /* Mark as removed. */
722 ovsrcu_set(&CONST_CAST(struct cls_rule
*, cls_rule
)->cls_match
, NULL
);
724 /* Remove 'cls_rule' from the subtable's rules list. */
725 rculist_remove(CONST_CAST(struct rculist
*, &cls_rule
->node
));
727 subtable
= find_subtable(cls
, cls_rule
->match
.mask
);
728 ovs_assert(subtable
);
731 for (i
= 0; i
< subtable
->n_indices
; i
++) {
732 ihash
[i
] = minimatch_hash_range(&cls_rule
->match
,
733 subtable
->index_maps
[i
],
734 &mask_offset
, &basis
);
736 hash
= minimatch_hash_range(&cls_rule
->match
, subtable
->index_maps
[i
],
737 &mask_offset
, &basis
);
739 head
= find_equal(subtable
, cls_rule
->match
.flow
, hash
);
741 /* Check if the rule is not the head rule. */
743 struct cls_match
*iter
;
745 /* Not the head rule, but potentially one with the same priority. */
746 /* Remove from the list of equal rules. */
747 FOR_EACH_RULE_IN_LIST_PROTECTED (iter
, prev
, head
) {
752 ovs_assert(iter
== rule
);
754 cls_match_remove(prev
, rule
);
759 /* 'rule' is the head rule. Check if there is another rule to
760 * replace 'rule' in the data structures. */
761 next
= cls_match_next_protected(rule
);
763 cmap_replace(&subtable
->rules
, &rule
->cmap_node
, &next
->cmap_node
,
768 /* 'rule' is last of the kind in the classifier, must remove from all the
769 * data structures. */
771 if (subtable
->ports_mask_len
) {
772 ovs_be32 masked_ports
= minimatch_get_ports(&cls_rule
->match
);
774 trie_remove_prefix(&subtable
->ports_trie
,
775 &masked_ports
, subtable
->ports_mask_len
);
777 for (i
= 0; i
< cls
->n_tries
; i
++) {
778 if (subtable
->trie_plen
[i
]) {
779 trie_remove(&cls
->tries
[i
], cls_rule
, subtable
->trie_plen
[i
]);
783 /* Remove rule node from indices. */
784 for (i
= 0; i
< subtable
->n_indices
; i
++) {
785 ccmap_dec(&subtable
->indices
[i
], ihash
[i
]);
787 n_rules
= cmap_remove(&subtable
->rules
, &rule
->cmap_node
, hash
);
790 destroy_subtable(cls
, subtable
);
793 if (subtable
->max_priority
== rule
->priority
794 && --subtable
->max_count
== 0) {
795 /* Find the new 'max_priority' and 'max_count'. */
796 int max_priority
= INT_MIN
;
797 CMAP_FOR_EACH (head
, cmap_node
, &subtable
->rules
) {
798 if (head
->priority
> max_priority
) {
799 max_priority
= head
->priority
;
800 subtable
->max_count
= 1;
801 } else if (head
->priority
== max_priority
) {
802 ++subtable
->max_count
;
805 subtable
->max_priority
= max_priority
;
806 pvector_change_priority(&cls
->subtables
, subtable
, max_priority
);
811 pvector_publish(&cls
->subtables
);
815 conj_set
= ovsrcu_get_protected(struct cls_conjunction_set
*,
818 ovsrcu_postpone(free
, conj_set
);
820 ovsrcu_postpone(cls_match_free_cb
, rule
);
826 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
827 * subtables which have a prefix match on the trie field, but whose prefix
828 * length is not indicated in 'match_plens'. For example, a subtable that
829 * has a 8-bit trie field prefix match can be skipped if
830 * !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
831 * must be unwildcarded to make datapath flow only match packets it should. */
833 const struct cls_trie
*trie
;
834 bool lookup_done
; /* Status of the lookup. */
835 uint8_t be32ofs
; /* U32 offset of the field in question. */
836 unsigned int maskbits
; /* Prefix length needed to avoid false matches. */
837 union trie_prefix match_plens
; /* Bitmask of prefix lengths with possible
842 trie_ctx_init(struct trie_ctx
*ctx
, const struct cls_trie
*trie
)
845 ctx
->be32ofs
= trie
->field
->flow_be32ofs
;
846 ctx
->lookup_done
= false;
849 struct conjunctive_match
{
850 struct hmap_node hmap_node
;
855 static struct conjunctive_match
*
856 find_conjunctive_match__(struct hmap
*matches
, uint64_t id
, uint32_t hash
)
858 struct conjunctive_match
*m
;
860 HMAP_FOR_EACH_IN_BUCKET (m
, hmap_node
, hash
, matches
) {
869 find_conjunctive_match(const struct cls_conjunction_set
*set
,
870 unsigned int max_n_clauses
, struct hmap
*matches
,
871 struct conjunctive_match
*cm_stubs
, size_t n_cm_stubs
,
874 const struct cls_conjunction
*c
;
876 if (max_n_clauses
< set
->min_n_clauses
) {
880 for (c
= set
->conj
; c
< &set
->conj
[set
->n
]; c
++) {
881 struct conjunctive_match
*cm
;
884 if (c
->n_clauses
> max_n_clauses
) {
888 hash
= hash_int(c
->id
, 0);
889 cm
= find_conjunctive_match__(matches
, c
->id
, hash
);
891 size_t n
= hmap_count(matches
);
893 cm
= n
< n_cm_stubs
? &cm_stubs
[n
] : xmalloc(sizeof *cm
);
894 hmap_insert(matches
, &cm
->hmap_node
, hash
);
896 cm
->clauses
= UINT64_MAX
<< (c
->n_clauses
& 63);
898 cm
->clauses
|= UINT64_C(1) << c
->clause
;
899 if (cm
->clauses
== UINT64_MAX
) {
908 free_conjunctive_matches(struct hmap
*matches
,
909 struct conjunctive_match
*cm_stubs
, size_t n_cm_stubs
)
911 if (hmap_count(matches
) > n_cm_stubs
) {
912 struct conjunctive_match
*cm
, *next
;
914 HMAP_FOR_EACH_SAFE (cm
, next
, hmap_node
, matches
) {
915 if (!(cm
>= cm_stubs
&& cm
< &cm_stubs
[n_cm_stubs
])) {
920 hmap_destroy(matches
);
923 /* Like classifier_lookup(), except that support for conjunctive matches can be
924 * configured with 'allow_conjunctive_matches'. That feature is not exposed
925 * externally because turning off conjunctive matches is only useful to avoid
926 * recursion within this function itself.
928 * 'flow' is non-const to allow for temporary modifications during the lookup.
929 * Any changes are restored before returning. */
930 static const struct cls_rule
*
931 classifier_lookup__(const struct classifier
*cls
, ovs_version_t version
,
932 struct flow
*flow
, struct flow_wildcards
*wc
,
933 bool allow_conjunctive_matches
)
935 struct trie_ctx trie_ctx
[CLS_MAX_TRIES
];
936 const struct cls_match
*match
;
937 /* Highest-priority flow in 'cls' that certainly matches 'flow'. */
938 const struct cls_match
*hard
= NULL
;
939 int hard_pri
= INT_MIN
; /* hard ? hard->priority : INT_MIN. */
941 /* Highest-priority conjunctive flows in 'cls' matching 'flow'. Since
942 * these are (components of) conjunctive flows, we can only know whether
943 * the full conjunctive flow matches after seeing multiple of them. Thus,
944 * we refer to these as "soft matches". */
945 struct cls_conjunction_set
*soft_stub
[64];
946 struct cls_conjunction_set
**soft
= soft_stub
;
947 size_t n_soft
= 0, allocated_soft
= ARRAY_SIZE(soft_stub
);
948 int soft_pri
= INT_MIN
; /* n_soft ? MAX(soft[*]->priority) : INT_MIN. */
950 /* Synchronize for cls->n_tries and subtable->trie_plen. They can change
951 * when table configuration changes, which happens typically only on
953 atomic_thread_fence(memory_order_acquire
);
955 /* Initialize trie contexts for find_match_wc(). */
956 for (int i
= 0; i
< cls
->n_tries
; i
++) {
957 trie_ctx_init(&trie_ctx
[i
], &cls
->tries
[i
]);
961 struct cls_subtable
*subtable
;
962 PVECTOR_FOR_EACH_PRIORITY (subtable
, hard_pri
+ 1, 2, sizeof *subtable
,
964 struct cls_conjunction_set
*conj_set
;
966 /* Skip subtables with no match, or where the match is lower-priority
967 * than some certain match we've already found. */
968 match
= find_match_wc(subtable
, version
, flow
, trie_ctx
, cls
->n_tries
,
970 if (!match
|| match
->priority
<= hard_pri
) {
974 conj_set
= ovsrcu_get(struct cls_conjunction_set
*, &match
->conj_set
);
976 /* 'match' isn't part of a conjunctive match. It's the best
977 * certain match we've got so far, since we know that it's
978 * higher-priority than hard_pri.
980 * (There might be a higher-priority conjunctive match. We can't
983 hard_pri
= hard
->priority
;
984 } else if (allow_conjunctive_matches
) {
985 /* 'match' is part of a conjunctive match. Add it to the list. */
986 if (OVS_UNLIKELY(n_soft
>= allocated_soft
)) {
987 struct cls_conjunction_set
**old_soft
= soft
;
990 soft
= xmalloc(allocated_soft
* sizeof *soft
);
991 memcpy(soft
, old_soft
, n_soft
* sizeof *soft
);
992 if (old_soft
!= soft_stub
) {
996 soft
[n_soft
++] = conj_set
;
998 /* Keep track of the highest-priority soft match. */
999 if (soft_pri
< match
->priority
) {
1000 soft_pri
= match
->priority
;
1005 /* In the common case, at this point we have no soft matches and we can
1006 * return immediately. (We do the same thing if we have potential soft
1007 * matches but none of them are higher-priority than our hard match.) */
1008 if (hard_pri
>= soft_pri
) {
1009 if (soft
!= soft_stub
) {
1012 return hard
? hard
->cls_rule
: NULL
;
1015 /* At this point, we have some soft matches. We might also have a hard
1016 * match; if so, its priority is lower than the highest-priority soft
1021 * Check whether soft matches are real matches. */
1023 /* Delete soft matches that are null. This only happens in second and
1024 * subsequent iterations of the soft match loop, when we drop back from
1025 * a high-priority soft match to a lower-priority one.
1027 * Also, delete soft matches whose priority is less than or equal to
1028 * the hard match's priority. In the first iteration of the soft
1029 * match, these can be in 'soft' because the earlier main loop found
1030 * the soft match before the hard match. In second and later iteration
1031 * of the soft match loop, these can be in 'soft' because we dropped
1032 * back from a high-priority soft match to a lower-priority soft match.
1034 * It is tempting to delete soft matches that cannot be satisfied
1035 * because there are fewer soft matches than required to satisfy any of
1036 * their conjunctions, but we cannot do that because there might be
1037 * lower priority soft or hard matches with otherwise identical
1038 * matches. (We could special case those here, but there's no
1039 * need--we'll do so at the bottom of the soft match loop anyway and
1040 * this duplicates less code.)
1042 * It's also tempting to break out of the soft match loop if 'n_soft ==
1043 * 1' but that would also miss lower-priority hard matches. We could
1044 * special case that also but again there's no need. */
1045 for (int i
= 0; i
< n_soft
; ) {
1046 if (!soft
[i
] || soft
[i
]->priority
<= hard_pri
) {
1047 soft
[i
] = soft
[--n_soft
];
1056 /* Find the highest priority among the soft matches. (We know this
1057 * must be higher than the hard match's priority; otherwise we would
1058 * have deleted all of the soft matches in the previous loop.) Count
1059 * the number of soft matches that have that priority. */
1062 for (int i
= 0; i
< n_soft
; i
++) {
1063 if (soft
[i
]->priority
> soft_pri
) {
1064 soft_pri
= soft
[i
]->priority
;
1066 } else if (soft
[i
]->priority
== soft_pri
) {
1070 ovs_assert(soft_pri
> hard_pri
);
1072 /* Look for a real match among the highest-priority soft matches.
1074 * It's unusual to have many conjunctive matches, so we use stubs to
1075 * avoid calling malloc() in the common case. An hmap has a built-in
1076 * stub for up to 2 hmap_nodes; possibly, we would benefit a variant
1077 * with a bigger stub. */
1078 struct conjunctive_match cm_stubs
[16];
1079 struct hmap matches
;
1081 hmap_init(&matches
);
1082 for (int i
= 0; i
< n_soft
; i
++) {
1085 if (soft
[i
]->priority
== soft_pri
1086 && find_conjunctive_match(soft
[i
], n_soft_pri
, &matches
,
1087 cm_stubs
, ARRAY_SIZE(cm_stubs
),
1089 uint32_t saved_conj_id
= flow
->conj_id
;
1090 const struct cls_rule
*rule
;
1093 rule
= classifier_lookup__(cls
, version
, flow
, wc
, false);
1094 flow
->conj_id
= saved_conj_id
;
1097 free_conjunctive_matches(&matches
,
1098 cm_stubs
, ARRAY_SIZE(cm_stubs
));
1099 if (soft
!= soft_stub
) {
1106 free_conjunctive_matches(&matches
, cm_stubs
, ARRAY_SIZE(cm_stubs
));
1108 /* There's no real match among the highest-priority soft matches.
1109 * However, if any of those soft matches has a lower-priority but
1110 * otherwise identical flow match, then we need to consider those for
1111 * soft or hard matches.
1113 * The next iteration of the soft match loop will delete any null
1114 * pointers we put into 'soft' (and some others too). */
1115 for (int i
= 0; i
< n_soft
; i
++) {
1116 if (soft
[i
]->priority
!= soft_pri
) {
1120 /* Find next-lower-priority flow with identical flow match. */
1121 match
= next_visible_rule_in_list(soft
[i
]->match
, version
);
1123 soft
[i
] = ovsrcu_get(struct cls_conjunction_set
*,
1126 /* The flow is a hard match; don't treat as a soft
1128 if (match
->priority
> hard_pri
) {
1130 hard_pri
= hard
->priority
;
1134 /* No such lower-priority flow (probably the common case). */
1140 if (soft
!= soft_stub
) {
1143 return hard
? hard
->cls_rule
: NULL
;
1146 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow' and
1147 * that is visible in 'version'. Returns a null pointer if no rules in 'cls'
1148 * match 'flow'. If multiple rules of equal priority match 'flow', returns one
1151 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
1152 * set of bits that were significant in the lookup. At some point
1153 * earlier, 'wc' should have been initialized (e.g., by
1154 * flow_wildcards_init_catchall()).
1156 * 'flow' is non-const to allow for temporary modifications during the lookup.
1157 * Any changes are restored before returning. */
1158 const struct cls_rule
*
1159 classifier_lookup(const struct classifier
*cls
, ovs_version_t version
,
1160 struct flow
*flow
, struct flow_wildcards
*wc
)
1162 return classifier_lookup__(cls
, version
, flow
, wc
, true);
1165 /* Finds and returns a rule in 'cls' with exactly the same priority and
1166 * matching criteria as 'target', and that is visible in 'version'.
1167 * Only one such rule may ever exist. Returns a null pointer if 'cls' doesn't
1168 * contain an exact match. */
1169 const struct cls_rule
*
1170 classifier_find_rule_exactly(const struct classifier
*cls
,
1171 const struct cls_rule
*target
,
1172 ovs_version_t version
)
1174 const struct cls_match
*head
, *rule
;
1175 const struct cls_subtable
*subtable
;
1177 subtable
= find_subtable(cls
, target
->match
.mask
);
1182 head
= find_equal(subtable
, target
->match
.flow
,
1183 miniflow_hash_in_minimask(target
->match
.flow
,
1184 target
->match
.mask
, 0));
1188 CLS_MATCH_FOR_EACH (rule
, head
) {
1189 if (rule
->priority
< target
->priority
) {
1190 break; /* Not found. */
1192 if (rule
->priority
== target
->priority
1193 && cls_match_visible_in_version(rule
, version
)) {
1194 return rule
->cls_rule
;
1200 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1201 * same matching criteria as 'target', and that is visible in 'version'.
1202 * Returns a null pointer if 'cls' doesn't contain an exact match visible in
1204 const struct cls_rule
*
1205 classifier_find_match_exactly(const struct classifier
*cls
,
1206 const struct match
*target
, int priority
,
1207 ovs_version_t version
)
1209 const struct cls_rule
*retval
;
1212 cls_rule_init(&cr
, target
, priority
);
1213 retval
= classifier_find_rule_exactly(cls
, &cr
, version
);
1214 cls_rule_destroy(&cr
);
1219 /* Checks if 'target' would overlap any other rule in 'cls' in 'version'. Two
1220 * rules are considered to overlap if both rules have the same priority and a
1221 * packet could match both, and if both rules are visible in the same version.
1223 * A trivial example of overlapping rules is two rules matching disjoint sets
1224 * of fields. E.g., if one rule matches only on port number, while another only
1225 * on dl_type, any packet from that specific port and with that specific
1226 * dl_type could match both, if the rules also have the same priority. */
1228 classifier_rule_overlaps(const struct classifier
*cls
,
1229 const struct cls_rule
*target
, ovs_version_t version
)
1231 struct cls_subtable
*subtable
;
1233 /* Iterate subtables in the descending max priority order. */
1234 PVECTOR_FOR_EACH_PRIORITY (subtable
, target
->priority
, 2,
1235 sizeof(struct cls_subtable
), &cls
->subtables
) {
1237 struct minimask mask
;
1238 uint64_t storage
[FLOW_U64S
];
1240 const struct cls_rule
*rule
;
1242 minimask_combine(&m
.mask
, target
->match
.mask
, &subtable
->mask
,
1245 RCULIST_FOR_EACH (rule
, node
, &subtable
->rules_list
) {
1246 if (rule
->priority
== target
->priority
1247 && miniflow_equal_in_minimask(target
->match
.flow
,
1248 rule
->match
.flow
, &m
.mask
)
1249 && cls_rule_visible_in_version(rule
, version
)) {
1257 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1258 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1259 * function returns true if, for every field:
1261 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1264 * - 'criteria' wildcards the field,
1266 * Conversely, 'rule' does not match 'criteria' and this function returns false
1267 * if, for at least one field:
1269 * - 'criteria' and 'rule' specify different values for the field, or
1271 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1273 * Equivalently, the truth table for whether a field matches is:
1278 * r +---------+---------+
1279 * i wild | yes | yes |
1281 * e +---------+---------+
1282 * r exact | no |if values|
1284 * a +---------+---------+
1286 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1287 * commands and by OpenFlow 1.0 aggregate and flow stats.
1289 * Ignores rule->priority. */
1291 cls_rule_is_loose_match(const struct cls_rule
*rule
,
1292 const struct minimatch
*criteria
)
1294 return (!minimask_has_extra(rule
->match
.mask
, criteria
->mask
)
1295 && miniflow_equal_in_minimask(rule
->match
.flow
, criteria
->flow
,
1302 rule_matches(const struct cls_rule
*rule
, const struct cls_rule
*target
,
1303 ovs_version_t version
)
1305 /* Rule may only match a target if it is visible in target's version. */
1306 return cls_rule_visible_in_version(rule
, version
)
1307 && (!target
|| miniflow_equal_in_minimask(rule
->match
.flow
,
1309 target
->match
.mask
));
1312 static const struct cls_rule
*
1313 search_subtable(const struct cls_subtable
*subtable
,
1314 struct cls_cursor
*cursor
)
1317 || !minimask_has_extra(&subtable
->mask
, cursor
->target
->match
.mask
)) {
1318 const struct cls_rule
*rule
;
1320 RCULIST_FOR_EACH (rule
, node
, &subtable
->rules_list
) {
1321 if (rule_matches(rule
, cursor
->target
, cursor
->version
)) {
1329 /* Initializes 'cursor' for iterating through rules in 'cls', and returns the
1332 * - If 'target' is null, or if the 'target' is a catchall target, the
1333 * cursor will visit every rule in 'cls' that is visible in 'version'.
1335 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1336 * such that cls_rule_is_loose_match(rule, target) returns true and that
1337 * the rule is visible in 'version'.
1339 * Ignores target->priority. */
1341 cls_cursor_start(const struct classifier
*cls
, const struct cls_rule
*target
,
1342 ovs_version_t version
)
1344 struct cls_cursor cursor
;
1345 struct cls_subtable
*subtable
;
1348 cursor
.target
= target
&& !cls_rule_is_catchall(target
) ? target
: NULL
;
1349 cursor
.version
= version
;
1352 /* Find first rule. */
1353 PVECTOR_CURSOR_FOR_EACH (subtable
, &cursor
.subtables
,
1354 &cursor
.cls
->subtables
) {
1355 const struct cls_rule
*rule
= search_subtable(subtable
, &cursor
);
1358 cursor
.subtable
= subtable
;
1367 static const struct cls_rule
*
1368 cls_cursor_next(struct cls_cursor
*cursor
)
1370 const struct cls_rule
*rule
;
1371 const struct cls_subtable
*subtable
;
1373 rule
= cursor
->rule
;
1374 subtable
= cursor
->subtable
;
1375 RCULIST_FOR_EACH_CONTINUE (rule
, node
, &subtable
->rules_list
) {
1376 if (rule_matches(rule
, cursor
->target
, cursor
->version
)) {
1381 PVECTOR_CURSOR_FOR_EACH_CONTINUE (subtable
, &cursor
->subtables
) {
1382 rule
= search_subtable(subtable
, cursor
);
1384 cursor
->subtable
= subtable
;
1392 /* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
1393 * or to null if all matching rules have been visited. */
1395 cls_cursor_advance(struct cls_cursor
*cursor
)
1397 cursor
->rule
= cls_cursor_next(cursor
);
1400 static struct cls_subtable
*
1401 find_subtable(const struct classifier
*cls
, const struct minimask
*mask
)
1403 struct cls_subtable
*subtable
;
1405 CMAP_FOR_EACH_WITH_HASH (subtable
, cmap_node
, minimask_hash(mask
, 0),
1406 &cls
->subtables_map
) {
1407 if (minimask_equal(mask
, &subtable
->mask
)) {
1414 /* Initializes 'map' with a subset of 'miniflow''s maps that includes only the
1415 * portions with u64-offset 'i' such that 'start' <= i < 'end'. Does not copy
1416 * any data from 'miniflow' to 'map'. */
1417 static struct flowmap
1418 miniflow_get_map_in_range(const struct miniflow
*miniflow
, uint8_t start
,
1424 map
= miniflow
->map
;
1426 /* Clear the bits before 'start'. */
1427 while (start
>= MAP_T_BITS
) {
1428 start
-= MAP_T_BITS
;
1430 map
.bits
[start
/ MAP_T_BITS
] = 0;
1433 flowmap_clear(&map
, ofs
, start
);
1436 /* Clear the bits starting at 'end'. */
1437 if (end
< FLOW_U64S
) {
1438 /* flowmap_clear() can handle at most MAP_T_BITS at a time. */
1439 ovs_assert(FLOW_U64S
- end
<= MAP_T_BITS
);
1440 flowmap_clear(&map
, end
, FLOW_U64S
- end
);
1445 /* The new subtable will be visible to the readers only after this. */
1446 static struct cls_subtable
*
1447 insert_subtable(struct classifier
*cls
, const struct minimask
*mask
)
1449 uint32_t hash
= minimask_hash(mask
, 0);
1450 struct cls_subtable
*subtable
;
1452 struct flowmap stage_map
;
1454 size_t count
= miniflow_n_values(&mask
->masks
);
1456 subtable
= xzalloc(sizeof *subtable
+ MINIFLOW_VALUES_SIZE(count
));
1457 cmap_init(&subtable
->rules
);
1458 miniflow_clone(CONST_CAST(struct miniflow
*, &subtable
->mask
.masks
),
1459 &mask
->masks
, count
);
1461 /* Init indices for segmented lookup, if any. */
1463 for (i
= 0; i
< cls
->n_flow_segments
; i
++) {
1464 stage_map
= miniflow_get_map_in_range(&mask
->masks
, prev
,
1465 cls
->flow_segments
[i
]);
1466 /* Add an index if it adds mask bits. */
1467 if (!flowmap_is_empty(stage_map
)) {
1468 ccmap_init(&subtable
->indices
[index
]);
1469 *CONST_CAST(struct flowmap
*, &subtable
->index_maps
[index
])
1473 prev
= cls
->flow_segments
[i
];
1475 /* Map for the final stage. */
1476 *CONST_CAST(struct flowmap
*, &subtable
->index_maps
[index
])
1477 = miniflow_get_map_in_range(&mask
->masks
, prev
, FLOW_U64S
);
1478 /* Check if the final stage adds any bits. */
1480 if (flowmap_is_empty(subtable
->index_maps
[index
])) {
1481 /* Remove the last index, as it has the same fields as the rules
1484 ccmap_destroy(&subtable
->indices
[index
]);
1487 *CONST_CAST(uint8_t *, &subtable
->n_indices
) = index
;
1489 for (i
= 0; i
< cls
->n_tries
; i
++) {
1490 subtable
->trie_plen
[i
] = minimask_get_prefix_len(mask
,
1491 cls
->tries
[i
].field
);
1495 ovsrcu_set_hidden(&subtable
->ports_trie
, NULL
);
1496 *CONST_CAST(int *, &subtable
->ports_mask_len
)
1497 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask
->masks
, tp_src
)));
1499 /* List of rules. */
1500 rculist_init(&subtable
->rules_list
);
1502 cmap_insert(&cls
->subtables_map
, &subtable
->cmap_node
, hash
);
1507 /* RCU readers may still access the subtable before it is actually freed. */
1509 destroy_subtable(struct classifier
*cls
, struct cls_subtable
*subtable
)
1513 pvector_remove(&cls
->subtables
, subtable
);
1514 cmap_remove(&cls
->subtables_map
, &subtable
->cmap_node
,
1515 minimask_hash(&subtable
->mask
, 0));
1517 ovs_assert(ovsrcu_get_protected(struct trie_node
*, &subtable
->ports_trie
)
1519 ovs_assert(cmap_is_empty(&subtable
->rules
));
1520 ovs_assert(rculist_is_empty(&subtable
->rules_list
));
1522 for (i
= 0; i
< subtable
->n_indices
; i
++) {
1523 ccmap_destroy(&subtable
->indices
[i
]);
1525 cmap_destroy(&subtable
->rules
);
1526 ovsrcu_postpone(free
, subtable
);
1529 static unsigned int be_get_bit_at(const ovs_be32 value
[], unsigned int ofs
);
1531 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1532 * lookup results. */
1534 check_tries(struct trie_ctx trie_ctx
[CLS_MAX_TRIES
], unsigned int n_tries
,
1535 const unsigned int field_plen
[CLS_MAX_TRIES
],
1536 const struct flowmap range_map
, const struct flow
*flow
,
1537 struct flow_wildcards
*wc
)
1541 /* Check if we could avoid fully unwildcarding the next level of
1542 * fields using the prefix tries. The trie checks are done only as
1543 * needed to avoid folding in additional bits to the wildcards mask. */
1544 for (j
= 0; j
< n_tries
; j
++) {
1545 /* Is the trie field relevant for this subtable, and
1546 is the trie field within the current range of fields? */
1547 if (field_plen
[j
] &&
1548 flowmap_is_set(&range_map
, trie_ctx
[j
].be32ofs
/ 2)) {
1549 struct trie_ctx
*ctx
= &trie_ctx
[j
];
1551 /* On-demand trie lookup. */
1552 if (!ctx
->lookup_done
) {
1553 memset(&ctx
->match_plens
, 0, sizeof ctx
->match_plens
);
1554 ctx
->maskbits
= trie_lookup(ctx
->trie
, flow
, &ctx
->match_plens
);
1555 ctx
->lookup_done
= true;
1557 /* Possible to skip the rest of the subtable if subtable's
1558 * prefix on the field is not included in the lookup result. */
1559 if (!be_get_bit_at(&ctx
->match_plens
.be32
, field_plen
[j
] - 1)) {
1560 /* We want the trie lookup to never result in unwildcarding
1561 * any bits that would not be unwildcarded otherwise.
1562 * Since the trie is shared by the whole classifier, it is
1563 * possible that the 'maskbits' contain bits that are
1564 * irrelevant for the partition relevant for the current
1565 * packet. Hence the checks below. */
1567 /* Check that the trie result will not unwildcard more bits
1568 * than this subtable would otherwise. */
1569 if (ctx
->maskbits
<= field_plen
[j
]) {
1570 /* Unwildcard the bits and skip the rest. */
1571 mask_set_prefix_bits(wc
, ctx
->be32ofs
, ctx
->maskbits
);
1572 /* Note: Prerequisite already unwildcarded, as the only
1573 * prerequisite of the supported trie lookup fields is
1574 * the ethertype, which is always unwildcarded. */
1577 /* Can skip if the field is already unwildcarded. */
1578 if (mask_prefix_bits_set(wc
, ctx
->be32ofs
, ctx
->maskbits
)) {
1587 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1588 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1589 * value has the correct value in 'target'.
1591 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1592 * target, mask) but this is faster because of the invariant that
1593 * flow->map and mask->masks.map are the same, and that this version
1594 * takes the 'wc'. */
1596 miniflow_and_mask_matches_flow(const struct miniflow
*flow
,
1597 const struct minimask
*mask
,
1598 const struct flow
*target
)
1600 const uint64_t *flowp
= miniflow_get_values(flow
);
1601 const uint64_t *maskp
= miniflow_get_values(&mask
->masks
);
1602 const uint64_t *target_u64
= (const uint64_t *)target
;
1605 FLOWMAP_FOR_EACH_MAP (map
, mask
->masks
.map
) {
1608 MAP_FOR_EACH_INDEX (idx
, map
) {
1609 if ((*flowp
++ ^ target_u64
[idx
]) & *maskp
++) {
1613 target_u64
+= MAP_T_BITS
;
1618 static inline const struct cls_match
*
1619 find_match(const struct cls_subtable
*subtable
, ovs_version_t version
,
1620 const struct flow
*flow
, uint32_t hash
)
1622 const struct cls_match
*head
, *rule
;
1624 CMAP_FOR_EACH_WITH_HASH (head
, cmap_node
, hash
, &subtable
->rules
) {
1625 if (OVS_LIKELY(miniflow_and_mask_matches_flow(&head
->flow
,
1628 /* Return highest priority rule that is visible. */
1629 CLS_MATCH_FOR_EACH (rule
, head
) {
1630 if (OVS_LIKELY(cls_match_visible_in_version(rule
, version
))) {
1640 static const struct cls_match
*
1641 find_match_wc(const struct cls_subtable
*subtable
, ovs_version_t version
,
1642 const struct flow
*flow
, struct trie_ctx trie_ctx
[CLS_MAX_TRIES
],
1643 unsigned int n_tries
, struct flow_wildcards
*wc
)
1645 if (OVS_UNLIKELY(!wc
)) {
1646 return find_match(subtable
, version
, flow
,
1647 flow_hash_in_minimask(flow
, &subtable
->mask
, 0));
1650 uint32_t basis
= 0, hash
;
1651 const struct cls_match
*rule
= NULL
;
1652 struct flowmap stages_map
= FLOWMAP_EMPTY_INITIALIZER
;
1653 unsigned int mask_offset
= 0;
1656 /* Try to finish early by checking fields in segments. */
1657 for (i
= 0; i
< subtable
->n_indices
; i
++) {
1658 if (check_tries(trie_ctx
, n_tries
, subtable
->trie_plen
,
1659 subtable
->index_maps
[i
], flow
, wc
)) {
1660 /* 'wc' bits for the trie field set, now unwildcard the preceding
1661 * bits used so far. */
1665 /* Accumulate the map used so far. */
1666 stages_map
= flowmap_or(stages_map
, subtable
->index_maps
[i
]);
1668 hash
= flow_hash_in_minimask_range(flow
, &subtable
->mask
,
1669 subtable
->index_maps
[i
],
1670 &mask_offset
, &basis
);
1672 if (!ccmap_find(&subtable
->indices
[i
], hash
)) {
1676 /* Trie check for the final range. */
1677 if (check_tries(trie_ctx
, n_tries
, subtable
->trie_plen
,
1678 subtable
->index_maps
[i
], flow
, wc
)) {
1681 hash
= flow_hash_in_minimask_range(flow
, &subtable
->mask
,
1682 subtable
->index_maps
[i
],
1683 &mask_offset
, &basis
);
1684 rule
= find_match(subtable
, version
, flow
, hash
);
1685 if (!rule
&& subtable
->ports_mask_len
) {
1686 /* The final stage had ports, but there was no match. Instead of
1687 * unwildcarding all the ports bits, use the ports trie to figure out a
1688 * smaller set of bits to unwildcard. */
1690 ovs_be32 value
, plens
, mask
;
1692 mask
= MINIFLOW_GET_BE32(&subtable
->mask
.masks
, tp_src
);
1693 value
= ((OVS_FORCE ovs_be32
*)flow
)[TP_PORTS_OFS32
] & mask
;
1694 mbits
= trie_lookup_value(&subtable
->ports_trie
, &value
, &plens
, 32);
1696 ((OVS_FORCE ovs_be32
*)&wc
->masks
)[TP_PORTS_OFS32
] |=
1697 mask
& be32_prefix_mask(mbits
);
1702 /* Must unwildcard all the fields, as they were looked at. */
1703 flow_wildcards_fold_minimask(wc
, &subtable
->mask
);
1707 /* Unwildcard the bits in stages so far, as they were used in determining
1708 * there is no match. */
1709 flow_wildcards_fold_minimask_in_map(wc
, &subtable
->mask
, stages_map
);
1713 static struct cls_match
*
1714 find_equal(const struct cls_subtable
*subtable
, const struct miniflow
*flow
,
1717 struct cls_match
*head
;
1719 CMAP_FOR_EACH_WITH_HASH (head
, cmap_node
, hash
, &subtable
->rules
) {
1720 if (miniflow_equal(&head
->flow
, flow
)) {
1727 /* A longest-prefix match tree. */
1729 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1730 * Prefixes are in the network byte order, and the offset 0 corresponds to
1731 * the most significant bit of the first byte. The offset can be read as
1732 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1734 raw_get_prefix(const ovs_be32 pr
[], unsigned int ofs
, unsigned int plen
)
1738 pr
+= ofs
/ 32; /* Where to start. */
1739 ofs
%= 32; /* How many bits to skip at 'pr'. */
1741 prefix
= ntohl(*pr
) << ofs
; /* Get the first 32 - ofs bits. */
1742 if (plen
> 32 - ofs
) { /* Need more than we have already? */
1743 prefix
|= ntohl(*++pr
) >> (32 - ofs
);
1745 /* Return with possible unwanted bits at the end. */
1749 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1750 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1751 * corresponds to the most significant bit of the first byte. The offset can
1752 * be read as "how many bits to skip from the start of the prefix starting at
1755 trie_get_prefix(const ovs_be32 pr
[], unsigned int ofs
, unsigned int plen
)
1760 if (plen
> TRIE_PREFIX_BITS
) {
1761 plen
= TRIE_PREFIX_BITS
; /* Get at most TRIE_PREFIX_BITS. */
1763 /* Return with unwanted bits cleared. */
1764 return raw_get_prefix(pr
, ofs
, plen
) & ~0u << (32 - plen
);
1767 /* Return the number of equal bits in 'n_bits' of 'prefix's MSBs and a 'value'
1768 * starting at "MSB 0"-based offset 'ofs'. */
1770 prefix_equal_bits(uint32_t prefix
, unsigned int n_bits
, const ovs_be32 value
[],
1773 uint64_t diff
= prefix
^ raw_get_prefix(value
, ofs
, n_bits
);
1774 /* Set the bit after the relevant bits to limit the result. */
1775 return raw_clz64(diff
<< 32 | UINT64_C(1) << (63 - n_bits
));
1778 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
1779 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
1781 trie_prefix_equal_bits(const struct trie_node
*node
, const ovs_be32 prefix
[],
1782 unsigned int ofs
, unsigned int plen
)
1784 return prefix_equal_bits(node
->prefix
, MIN(node
->n_bits
, plen
- ofs
),
1788 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
1789 * be greater than 31. */
1791 be_get_bit_at(const ovs_be32 value
[], unsigned int ofs
)
1793 return (((const uint8_t *)value
)[ofs
/ 8] >> (7 - ofs
% 8)) & 1u;
1796 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
1797 * be between 0 and 31, inclusive. */
1799 get_bit_at(const uint32_t prefix
, unsigned int ofs
)
1801 return (prefix
>> (31 - ofs
)) & 1u;
1804 /* Create new branch. */
1805 static struct trie_node
*
1806 trie_branch_create(const ovs_be32
*prefix
, unsigned int ofs
, unsigned int plen
,
1807 unsigned int n_rules
)
1809 struct trie_node
*node
= xmalloc(sizeof *node
);
1811 node
->prefix
= trie_get_prefix(prefix
, ofs
, plen
);
1813 if (plen
<= TRIE_PREFIX_BITS
) {
1814 node
->n_bits
= plen
;
1815 ovsrcu_set_hidden(&node
->edges
[0], NULL
);
1816 ovsrcu_set_hidden(&node
->edges
[1], NULL
);
1817 node
->n_rules
= n_rules
;
1818 } else { /* Need intermediate nodes. */
1819 struct trie_node
*subnode
= trie_branch_create(prefix
,
1820 ofs
+ TRIE_PREFIX_BITS
,
1821 plen
- TRIE_PREFIX_BITS
,
1823 int bit
= get_bit_at(subnode
->prefix
, 0);
1824 node
->n_bits
= TRIE_PREFIX_BITS
;
1825 ovsrcu_set_hidden(&node
->edges
[bit
], subnode
);
1826 ovsrcu_set_hidden(&node
->edges
[!bit
], NULL
);
1833 trie_node_destroy(const struct trie_node
*node
)
1835 ovsrcu_postpone(free
, CONST_CAST(struct trie_node
*, node
));
1838 /* Copy a trie node for modification and postpone delete the old one. */
1839 static struct trie_node
*
1840 trie_node_rcu_realloc(const struct trie_node
*node
)
1842 struct trie_node
*new_node
= xmalloc(sizeof *node
);
1845 trie_node_destroy(node
);
1851 trie_destroy(rcu_trie_ptr
*trie
)
1853 struct trie_node
*node
= ovsrcu_get_protected(struct trie_node
*, trie
);
1856 ovsrcu_set_hidden(trie
, NULL
);
1857 trie_destroy(&node
->edges
[0]);
1858 trie_destroy(&node
->edges
[1]);
1859 trie_node_destroy(node
);
1864 trie_is_leaf(const struct trie_node
*trie
)
1867 return !ovsrcu_get(struct trie_node
*, &trie
->edges
[0])
1868 && !ovsrcu_get(struct trie_node
*, &trie
->edges
[1]);
1872 mask_set_prefix_bits(struct flow_wildcards
*wc
, uint8_t be32ofs
,
1873 unsigned int n_bits
)
1875 ovs_be32
*mask
= &((ovs_be32
*)&wc
->masks
)[be32ofs
];
1878 for (i
= 0; i
< n_bits
/ 32; i
++) {
1879 mask
[i
] = OVS_BE32_MAX
;
1882 mask
[i
] |= htonl(~0u << (32 - n_bits
% 32));
1887 mask_prefix_bits_set(const struct flow_wildcards
*wc
, uint8_t be32ofs
,
1888 unsigned int n_bits
)
1890 ovs_be32
*mask
= &((ovs_be32
*)&wc
->masks
)[be32ofs
];
1892 ovs_be32 zeroes
= 0;
1894 for (i
= 0; i
< n_bits
/ 32; i
++) {
1898 zeroes
|= ~mask
[i
] & htonl(~0u << (32 - n_bits
% 32));
1901 return !zeroes
; /* All 'n_bits' bits set. */
1904 static rcu_trie_ptr
*
1905 trie_next_edge(struct trie_node
*node
, const ovs_be32 value
[],
1908 return node
->edges
+ be_get_bit_at(value
, ofs
);
1911 static const struct trie_node
*
1912 trie_next_node(const struct trie_node
*node
, const ovs_be32 value
[],
1915 return ovsrcu_get(struct trie_node
*,
1916 &node
->edges
[be_get_bit_at(value
, ofs
)]);
1919 /* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
1922 be_set_bit_at(ovs_be32 value
[], unsigned int ofs
)
1924 ((uint8_t *)value
)[ofs
/ 8] |= 1u << (7 - ofs
% 8);
1927 /* Returns the number of bits in the prefix mask necessary to determine a
1928 * mismatch, in case there are longer prefixes in the tree below the one that
1930 * '*plens' will have a bit set for each prefix length that may have matching
1931 * rules. The caller is responsible for clearing the '*plens' prior to
1935 trie_lookup_value(const rcu_trie_ptr
*trie
, const ovs_be32 value
[],
1936 ovs_be32 plens
[], unsigned int n_bits
)
1938 const struct trie_node
*prev
= NULL
;
1939 const struct trie_node
*node
= ovsrcu_get(struct trie_node
*, trie
);
1940 unsigned int match_len
= 0; /* Number of matching bits. */
1942 for (; node
; prev
= node
, node
= trie_next_node(node
, value
, match_len
)) {
1943 unsigned int eqbits
;
1944 /* Check if this edge can be followed. */
1945 eqbits
= prefix_equal_bits(node
->prefix
, node
->n_bits
, value
,
1947 match_len
+= eqbits
;
1948 if (eqbits
< node
->n_bits
) { /* Mismatch, nothing more to be found. */
1949 /* Bit at offset 'match_len' differed. */
1950 return match_len
+ 1; /* Includes the first mismatching bit. */
1952 /* Full match, check if rules exist at this prefix length. */
1953 if (node
->n_rules
> 0) {
1954 be_set_bit_at(plens
, match_len
- 1);
1956 if (match_len
>= n_bits
) {
1957 return n_bits
; /* Full prefix. */
1960 /* node == NULL. Full match so far, but we tried to follow an
1961 * non-existing branch. Need to exclude the other branch if it exists
1962 * (it does not if we were called on an empty trie or 'prev' is a leaf
1964 return !prev
|| trie_is_leaf(prev
) ? match_len
: match_len
+ 1;
1968 trie_lookup(const struct cls_trie
*trie
, const struct flow
*flow
,
1969 union trie_prefix
*plens
)
1971 const struct mf_field
*mf
= trie
->field
;
1973 /* Check that current flow matches the prerequisites for the trie
1974 * field. Some match fields are used for multiple purposes, so we
1975 * must check that the trie is relevant for this flow. */
1976 if (mf_are_prereqs_ok(mf
, flow
, NULL
)) {
1977 return trie_lookup_value(&trie
->root
,
1978 &((ovs_be32
*)flow
)[mf
->flow_be32ofs
],
1979 &plens
->be32
, mf
->n_bits
);
1981 memset(plens
, 0xff, sizeof *plens
); /* All prefixes, no skipping. */
1982 return 0; /* Value not used in this case. */
1985 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
1986 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
1987 * 'miniflow_index' is not NULL. */
1989 minimask_get_prefix_len(const struct minimask
*minimask
,
1990 const struct mf_field
*mf
)
1992 unsigned int n_bits
= 0, mask_tz
= 0; /* Non-zero when end of mask seen. */
1993 uint8_t be32_ofs
= mf
->flow_be32ofs
;
1994 uint8_t be32_end
= be32_ofs
+ mf
->n_bytes
/ 4;
1996 for (; be32_ofs
< be32_end
; ++be32_ofs
) {
1997 uint32_t mask
= ntohl(minimask_get_be32(minimask
, be32_ofs
));
1999 /* Validate mask, count the mask length. */
2002 return 0; /* No bits allowed after mask ended. */
2005 if (~mask
& (~mask
+ 1)) {
2006 return 0; /* Mask not contiguous. */
2008 mask_tz
= ctz32(mask
);
2009 n_bits
+= 32 - mask_tz
;
2017 * This is called only when mask prefix is known to be CIDR and non-zero.
2018 * Relies on the fact that the flow and mask have the same map, and since
2019 * the mask is CIDR, the storage for the flow field exists even if it
2020 * happened to be zeros.
2022 static const ovs_be32
*
2023 minimatch_get_prefix(const struct minimatch
*match
, const struct mf_field
*mf
)
2025 size_t u64_ofs
= mf
->flow_be32ofs
/ 2;
2027 return (OVS_FORCE
const ovs_be32
*)miniflow_get__(match
->flow
, u64_ofs
)
2028 + (mf
->flow_be32ofs
& 1);
2031 /* Insert rule in to the prefix tree.
2032 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2035 trie_insert(struct cls_trie
*trie
, const struct cls_rule
*rule
, int mlen
)
2037 trie_insert_prefix(&trie
->root
,
2038 minimatch_get_prefix(&rule
->match
, trie
->field
), mlen
);
2042 trie_insert_prefix(rcu_trie_ptr
*edge
, const ovs_be32
*prefix
, int mlen
)
2044 struct trie_node
*node
;
2047 /* Walk the tree. */
2048 for (; (node
= ovsrcu_get_protected(struct trie_node
*, edge
));
2049 edge
= trie_next_edge(node
, prefix
, ofs
)) {
2050 unsigned int eqbits
= trie_prefix_equal_bits(node
, prefix
, ofs
, mlen
);
2052 if (eqbits
< node
->n_bits
) {
2053 /* Mismatch, new node needs to be inserted above. */
2054 int old_branch
= get_bit_at(node
->prefix
, eqbits
);
2055 struct trie_node
*new_parent
;
2057 new_parent
= trie_branch_create(prefix
, ofs
- eqbits
, eqbits
,
2058 ofs
== mlen
? 1 : 0);
2059 /* Copy the node to modify it. */
2060 node
= trie_node_rcu_realloc(node
);
2061 /* Adjust the new node for its new position in the tree. */
2062 node
->prefix
<<= eqbits
;
2063 node
->n_bits
-= eqbits
;
2064 ovsrcu_set_hidden(&new_parent
->edges
[old_branch
], node
);
2066 /* Check if need a new branch for the new rule. */
2068 ovsrcu_set_hidden(&new_parent
->edges
[!old_branch
],
2069 trie_branch_create(prefix
, ofs
, mlen
- ofs
,
2072 ovsrcu_set(edge
, new_parent
); /* Publish changes. */
2075 /* Full match so far. */
2078 /* Full match at the current node, rule needs to be added here. */
2083 /* Must insert a new tree branch for the new rule. */
2084 ovsrcu_set(edge
, trie_branch_create(prefix
, ofs
, mlen
- ofs
, 1));
2087 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2090 trie_remove(struct cls_trie
*trie
, const struct cls_rule
*rule
, int mlen
)
2092 trie_remove_prefix(&trie
->root
,
2093 minimatch_get_prefix(&rule
->match
, trie
->field
), mlen
);
2096 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2099 trie_remove_prefix(rcu_trie_ptr
*root
, const ovs_be32
*prefix
, int mlen
)
2101 struct trie_node
*node
;
2102 rcu_trie_ptr
*edges
[sizeof(union trie_prefix
) * CHAR_BIT
];
2103 int depth
= 0, ofs
= 0;
2105 /* Walk the tree. */
2106 for (edges
[0] = root
;
2107 (node
= ovsrcu_get_protected(struct trie_node
*, edges
[depth
]));
2108 edges
[++depth
] = trie_next_edge(node
, prefix
, ofs
)) {
2109 unsigned int eqbits
= trie_prefix_equal_bits(node
, prefix
, ofs
, mlen
);
2111 if (eqbits
< node
->n_bits
) {
2112 /* Mismatch, nothing to be removed. This should never happen, as
2113 * only rules in the classifier are ever removed. */
2114 break; /* Log a warning. */
2116 /* Full match so far. */
2120 /* Full prefix match at the current node, remove rule here. */
2121 if (!node
->n_rules
) {
2122 break; /* Log a warning. */
2126 /* Check if can prune the tree. */
2127 while (!node
->n_rules
) {
2128 struct trie_node
*next
,
2129 *edge0
= ovsrcu_get_protected(struct trie_node
*,
2131 *edge1
= ovsrcu_get_protected(struct trie_node
*,
2134 if (edge0
&& edge1
) {
2135 break; /* A branching point, cannot prune. */
2138 /* Else have at most one child node, remove this node. */
2139 next
= edge0
? edge0
: edge1
;
2142 if (node
->n_bits
+ next
->n_bits
> TRIE_PREFIX_BITS
) {
2143 break; /* Cannot combine. */
2145 next
= trie_node_rcu_realloc(next
); /* Modify. */
2147 /* Combine node with next. */
2148 next
->prefix
= node
->prefix
| next
->prefix
>> node
->n_bits
;
2149 next
->n_bits
+= node
->n_bits
;
2151 /* Update the parent's edge. */
2152 ovsrcu_set(edges
[depth
], next
); /* Publish changes. */
2153 trie_node_destroy(node
);
2155 if (next
|| !depth
) {
2156 /* Branch not pruned or at root, nothing more to do. */
2159 node
= ovsrcu_get_protected(struct trie_node
*,
2165 /* Cannot go deeper. This should never happen, since only rules
2166 * that actually exist in the classifier are ever removed. */
2170 #define CLS_MATCH_POISON (struct cls_match *)(UINTPTR_MAX / 0xf * 0xb)
2173 cls_match_free_cb(struct cls_match
*rule
)
2175 ovsrcu_set_hidden(&rule
->next
, CLS_MATCH_POISON
);